This invention relates to the enrichment of foods and beverages with added naturally occurring agents and to methods of preparing such agents from waste products generated in agricultural food processing.
Many different crops are grown, harvested and processed into foods, beverages, nutritional supplements and the like. Large quantities of agricultural waste products are generated during crop processing. Typically, these include fruit skin and pits resulting from fruit crops such as peaches, apricots, cherries, plums, etc. or the xe2x80x9ccoffee cherryxe2x80x9d husks that are removed from coffee beans in the processing of coffee. Disposing of these waste products can cause serious environmental problems. Such waste products are generally incinerated, sometimes as auxiliary energy sources, or buried in landfills.
In the past no significant use has been developed for coffee cherries. Generally, coffee cherry pulp is simply disposed in a land fill. Uses exist for only a small portion of the fruit processing waste material.
Many of these waste products are very rich in useful ingredients, in particular in antioxidants that protect the seed from being damaged by a variety of naturally occurring free radicals and/or ultraviolet and other radiation to which the plants are exposed during the growing season. Using these waste products in foodstuffs and the like has been hampered by the presence of significant quantity of ingredients that protect the plant from their natural environmental enemies. These xe2x80x9cnatural pesticidesxe2x80x9d may be toxic to humans as, for example tomatine in tomato skin and solanine in potato skin. Also, some synthetic pesticide residues may well be present in the waste products. These problems make recycling the waste into food products difficult, if not impossible.
Thus, there is a continuing need for methods of reducing the amount of waste generated in growing and processing foodstuffs, that will recover valuable agents, such as antioxidants, that are present in agricultural waste and that will improve the quality and nutritional content of the foodstuffs, the processing of which generated the waste.
The above-noted problems, and others, are overcome in accordance with this invention by a process that basically includes selective extraction of antioxidants and other useful natural products from agricultural waste and returning them to the food product, drink or nutritional supplement that generated the wastes during agricultural crop processing.
While any suitable agricultural waste can be used in this novel process, it is particularly applicable to coffee cherries (the pulp that remains after removal of coffee beans). Waste, such as skins and pits remaining from processing fruit such as peaches, apricots, plums, citrus, bananas, etc., may also be processed in accordance with this invention. Of particular interest is the recovery of antioxidants and the reintroduction of the antioxidants into the finished product that generated the waste.
In the case of coffee cherries, caffeine can be recovered from the coffee cherry waste and used for other purposes such as in soft drinks, pharaceuticals, etc. Antioxidants recovered from coffee cherries can be beneficially added to coffee, such as ground coffee or freeze-dried coffee.
Antioxidants recovered from fruit waste can be added to the fruit product, such as fruit drinks, canned or frozen fruit, etc. The final product is thus entirely natural, containing only ingredients present in the crop as harvested. In order to prevent pesticide residue from passing with the beneficial ingredients, the crop should be grown without use of pesticides. In some cases it may be possible to completely remove all pesticide residue.
Typical antioxidants that are recovered include proanthocyanidins, catechin, epicatechin, chlorogenic acid, ferulic acid, caffeic acid, and various polyphenols. In addition to antioxidants, other natural products present in the waste can be recovered and reintroduced, such as various vitamins (e.g., vitamin C, vitamin E), oligo-saccharides, poly-saccharides and amino acids.
In general, the waste products are in the form of a wet mass, typically wet coffee cherry pulp, wet skins and kernels from various fruit, etc. This mass is dried at low temperature, typically room temperature, to avoid any thermal degradation of the material. Preferably, the waste material is initially dried to a low moisture mass. Typically, the material is pressed, such as in a continuous belt filter press to remove most of the water, leaving the pressed materials with a moisture content typically of about 20 wt %.
The pressed and at least partially dried raw material is then directly extracted with water or an organic solvent that is partially miscible with water at room or slightly elevated temperature, up to about 100xc2x0 C. Some organic solvents and water form azeotropic mixtures suitable for azeotropic distillation (azeotropic removal of water).
After the desired agents are extracted, the water is removed from the extract, such as by vacuum drying or freeze-drying at a lower temperature, while the organic solvent (if used) is removed, usually by vacuum distillation, at a lower temperature to avoid thermal degradation of any of the extract""s ingredients that may be sensitive to elevated temperatures.
Finally the antioxidants and any other extracted material are added back to the very same final food product as that generated the agricultural wastes. Thus, the final product will contain only natural material present in the original crop but will be enriched with antioxidants and other useful material that originally and naturally belong to the original crop. The final fruit juice, processed fruit, or coffee will be all natural but xe2x80x9chealthierxe2x80x9d than present similar products.